I-COST
A valid certificate is only one part of readiness
A subcontractor can pass prequalification and still arrive on a project without the right task-specific evidence. An insurance certificate does not show that an operative is competent for a particular installation. A training card does not establish that a proposed material meets the specification.
A useful UK construction compliance review in 2026 asks three separate questions: what does the law require for this location and role, what does the contract require, and what evidence demonstrates that the actual work meets those requirements? Assign an owner to each answer.
Separate statutory duties from assessment schemes
CDM duties and competence
HSE's contractor guidance under CDM 2015 explains responsibilities for planning, managing and monitoring work and checking workers' skills, knowledge, training and experience. These duties include subcontractors. A prequalification badge does not replace the contractor's responsibility to manage its own work.
CDM 2015 applies in Great Britain; Northern Ireland has its own framework. Check the project's jurisdiction and role appointments. Keep task planning, induction and supervision evidence proportionate to the risks rather than treating an office file as proof that site arrangements are effective.
Building regulations duties in England
The government's building-control circular identifies dutyholder and competence changes applying from 1 October 2023 in England. These are existing requirements, not a new UK-wide rule introduced in 2026. Check transitional arrangements where relevant.
The Building Safety Regulator's duties and competence guidance explains responsibilities and additional requirements for higher-risk building work. Establish the applicable building category and approval process with the project team. Do not assume that an England-specific procedure applies unchanged in Scotland, Wales or Northern Ireland.
Prequalification: check the version and client requirement
The Build UK Common Assessment Standard is an industry prequalification framework, not an Act of Parliament. Certification can be a condition imposed by a client or procurement process. Confirm the required assessment level and recognised assessment body before paying for overlapping assessments.
As checked on 28 October 2026, Build UK's guidance identifies Version 5 and announces Version 6 for 1 November 2026. That future publication is not an effective statutory date. Check the published revision and your next assessment requirements when it becomes available. Build UK describes annual certification and desktop and site-based assessment options.
Maintain a requirement register identifying the source of each obligation: legislation, contract, assessment scheme or company policy. This prevents a voluntary standard being presented as universal law while still treating a contractual certification requirement seriously.
Practical subcontractor compliance checklist
| Check | Evidence and follow-up |
|---|---|
| Scope and role | Record appointments, design responsibilities and any work outside competence. |
| People and supervision | Review task-specific skills, training, inductions and named supervisors. |
| Risk controls | Review work methods, current site conditions and interfaces with other trades. |
| Supplier assessment | Check client-required certification, assessment scope, expiry and exclusions. |
| Insurance | Match cover and declared activities to contractual requirements with broker advice. |
| Products and changes | Retain specified product evidence, approvals and authorised substitution records. |
| Inspection and handover | Agree inspection points, test records, defect closeout and required handover information. |
| Records | Assign owners, controlled revisions, access permissions and retention arrangements. |
Records must describe what was actually installed
Give each record a project, package, location, date, revision and responsible person. Link an approved substitution to the purchase order and installation evidence so the handover information does not describe a product that was never used. Retain superseded versions where needed for traceability, with the current approved issue clearly identified.
For example, a fire-stopping subcontractor should agree the required installation and inspection evidence with the project team before work starts. A supplier invoice alone cannot establish that an assembly was correctly installed. The evidence set must match the work and the applicable technical requirements.
The embodied-carbon guide covers another evidence trail: material quantities and environmental data. Client carbon reporting requests should be identified separately from statutory building and safety duties.
Practical takeaway
Review one live package from appointment to handover. List missing evidence, expiring documents and unapproved changes with an owner and deadline. Use competent health-and-safety, technical or legal advice for uncertain obligations. Commercial software can help organise supporting transactions, but purchasing it does not certify compliance.
Keep commercial evidence connected to the job
I-Cost documents supplier quotations, order revisions, delivery records and cost reports. These may support commercial traceability; this local code does not verify a dedicated compliance document-management or certification system.
Frequently asked questions
Is Common Assessment Standard certification a legal requirement for every subcontractor?
It is an industry assessment framework. A client or procurement process may require it, but certification is not a substitute for complying with applicable law.
Are building regulations requirements identical across the UK?
No. Building regulations are jurisdiction-specific. The England guidance cited here must not be applied automatically to other UK nations.
What should happen when a material is substituted?
Obtain the required technical and contractual approvals, update controlled records and retain evidence of what was actually installed.
Does I-Cost certify subcontractor compliance?
No such capability is verified in the local website code. Commercial transaction records can support traceability but do not establish statutory or technical compliance.
